Why The Query Works In Query Analyser And Doesn't Work In Reporting Service ?

Hello everybody,



I'm developing a report using the following structure :



declare @sql as nvarchar(4000)

declare @where as nvarchar(2000)



set @sql = 'select ....'



If <conditional1>

begin

set @where = 'some where'

end



If <conditional2>

begin

set @where = 'some where'

end



set @sql = @sql + @where



exec(@sql)



I run it in query analyser and works fine, but when I try to run in Reporting Services, Visual studio stops responding and the cpu reaches 100 %.



I realize that when I cut off the if clauses, then it works at Reporting services.

Does anybody know what is happening?

Why the query works in query analyser and doesn't work in Reporting Service ?



Thanks,



Maurício